1. Field of the Invention
The present disclosure relates to a liquid crystal display device, and more particularly, a liquid crystal display device having touch sensors embedded therein which achieves weight and thickness reduction, a method for driving the same, and a method for fabricating the same.
2. Discussion of the Related Art
Touch screens enabling input of data by touching a screen of various display devices are widely applied as data input devices for computer systems. The touch screens allow a user to simply touch a screen by hand or using a stylus so as to move or select displayed data, and thus are easily used by men and women of all ages.
A touch screen senses touch and a touched position generated on a screen of a display device and outputs touch data, and a computer system analyzes the touch data and performs instructions. As the display device, a flat panel display device, such as a liquid crystal display (LCD) device, a plasma display panel (PDP) device, or an organic light emitting diode (OLED) device, is mainly used.
As to types of touch screens, there are a resistive type, a capacitive type, an infrared type, an ultrasonic type, and an electromagnetic type according to sensing principles. Among these types, the resistive type and the capacitive type are advantageous in terms of manufacturing costs, thus being widely used.
A resistive type touch screen recognizes touch by sensing a change in voltage generated by contact between upper and lower resistive films (transparent conductive films) by touch pressure. However, the resistive type touch screen has the disadvantage that the touch screen or a display device can be easily damaged due to the touch pressure. Also, light transmittance is lowered due to light scattering effect of an air layer between the resistive films.
A capacitive type touch screen, which compensates for the disadvantages of the resistive type touch screen, recognizes touch by sensing a change in capacitance generated by movement of a small amount of electric charge to a touch point when the touch is carried out by a conductor, such as a human body or a stylus. The capacitive type touch screen, which uses tempered glass, has high durability, high light transmittance, and excellent touch sensing ability, thereby enabling multi-touch sensing and thus attracting attention.
In general, a touch screen is manufactured in the shape of a panel, and is attached to the upper surface of a display device, thus enabling a touch input function. However, a display device having a touch panel attached thereto, in which the touch panel is manufactured separately from the display device and then is attached to the display device, raises manufacturing costs and increases the overall thickness and weight of a system, thus causing deterioration of mobility or design limitations.